CD8A and neoplasm: Previous studies have demonstrated that myeloid ADO receptor A2 (A2AR) or ADO receptor B2 (A2BR) deficient mice exhibit elevated expression levels of costimulatory molecules CD86 and major histocompatibility complex II (MHC II, markers of the activation and maturation of antigen-presenting cells) on APCs, as well as increased CD8+ T cell activation and proliferation, higher levels of IFN-γ secretion on APCs, and slower tumor growth (25, 35).